Chassis-level thermal interface component for transfer of heat from an electronic component of a computer system

ABSTRACT

A computer system is described of the kind having a frame and a plurality of server unit subassemblies that are insertable into the frame. Each server unit subassembly has a chassis component which engages with a frame component on the frame. Heat can transfer from the chassis component to the frame component, but the server unit subassembly can still be moved out of the frame. In one embodiment, an air duct is located over a plurality of the frame components. Heat transfers from the frame components to air flowing through the duct. A modified capillary pumped loop is used to transfer heat from a processor of the server unit subassembly to thermal components on the frame.

BACKGROUND OF THE INVENTION

[0001] 1). Field of the Invention

[0002] This invention relates to a computer system.

[0003] 2). Discussion of Related Art

[0004] A server computer system usually includes a support frame and aplurality of server unit subassemblies that are insertable into thesupport frame. Each server unit subassembly has a processor whichgenerates heat when being operated. The processor of each server unitsubassembly usually generates a large amount of heat and removal of theheat may be problematic, especially if a large number of server unitsubassemblies are located on the support frame in a compact arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The invention is described by way of example with reference tothe accompanying drawings, wherein:

[0006]FIG. 1 is a perspective view of components of a server computersystem, according to an embodiment of the invention;

[0007]FIG. 2 is a perspective view of a frame-level thermal interfacecomponent forming part of the embodiment of FIG. 1;

[0008]FIG. 3 is a cross-sectional side view of components of the servercomputer system of FIG. 1;

[0009]FIG. 4 is a perspective view from one side of a chassis-levelthermal interface component forming part of the embodiment of FIG. 1;

[0010]FIG. 5 is a perspective view from another side of thechassis-level thermal interface component of FIG. 4;

[0011]FIG. 6 is an exploded perspective view of the chassis-levelthermal interface component of FIG. 4;

[0012]FIG. 7 is an enlarged perspective view of components of theembodiment of FIG. 1 after engagement of the chassis-level thermalinterface component with the frame-level thermal interface component;

[0013]FIG. 8 is a perspective view of the server computer system of FIG.1, further illustrating an air duct thereof before mounting of the airduct;

[0014]FIG. 9 is a perspective view of the components shown in FIG. 8after mounting of the air duct;

[0015]FIG. 10 is a perspective view of a floating support board andrelated components forming part of the server computer system of FIG. 1;

[0016]FIG. 11 is a perspective view from an opposing side of thecomponents of FIG. 10;

[0017]FIG. 12 is a side view illustrating a ratchet mechanism formingpart of the server computer system of FIG. 1;

[0018]FIG. 13 is a perspective view of the server computer system ofFIG. 1, further illustrating additional server unit subassembliesthereof;

[0019]FIG. 14 is a perspective view of a frame-level thermal interfacecomponent according to another embodiment of the invention;

[0020]FIG. 15 is a perspective view from an opposing side of theframe-level thermal interface component of FIG. 14; and

[0021]FIG. 16 is a perspective view of a further computer framesubassembly, with includes a plurality of the frame-level thermalinterface components of FIG. 14, together with related inlet and outletpipes for flow of liquid coolant.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Throughout the following description, specific details are setforth in order to provide a more thorough understanding of theinvention. However, the invention may be practiced without theseparticulars. In other instances, well-known elements have not been shownor described in detail to avoid unnecessarily obscuring the presentinvention.

[0023]FIG. 1 of the accompanying drawings illustrates a portion of aserver computer system 20 according to an embodiment of the invention,including a portion of a server computer frame subassembly 22 and oneserver unit subassembly 24.

[0024] The server computer frame subassembly 22 includes a support frame26 and a frame-level thermal interface component 28. The support frame26 includes four vertically extending supports 30, two side rails 32,and a rear structural member 34. One of the side rails 32A has a frontend secured to a front right one of the vertically extending supports30A, and a rear end secured to a rear right one of the verticallyextending supports 30B. The other side rail 32B has a front end securedto a front left one of the vertically extending supports 30C, and a rearend secured to a rear left one of the vertically extending supports 30D.The side rails 32A and 32B extend parallel to one another from a frontto a rear of the support frame 26. The rear structural member 34 hasopposing ends secured to the right rear and the left rear ones of thevertically extending supports 30B and 30D, respectively.

[0025]FIG. 2 illustrates the frame-level thermal interface component 28in more detail. The frame-level thermal interface component 28 includesa frame-level thermal interface subcomponent 36, a first set of fins 38,and a second set of fins 40.

[0026] The frame-level thermal interface subcomponent 36 has a width 42,a height 44, and a depth 46. The depth 46 is slightly more than theheight 44, and the width 42 is approximately five times as much as theheight 44.

[0027] An outer tapered recessed surface 48 is formed in a front of theframe-level thermal interface subcomponent 36. The recessed surface 48has a lower portion 50 and an upper portion 52. The portions 50 and 52are entirely straight, and are at an angle of approximately 30° relativeto one another. The lower portion 50 is at an angle of approximately 55°relative to horizontal, and the upper portion 52 is at an angle ofapproximately 5° relative to horizontal. The recessed surface 48 has aconstant cross-section along its width 42. Profiles of the recessedsurface 48 at various vertical planes spaced horizontally along thewidth 42 are the same as the “V”-shape that can be seen at the end ofthe frame-level thermal interface subcomponent 36. The recessed surface48 has height and a width, with the width being approximately threetimes as much as the height.

[0028] The profiled shape of the recessed surface 48 provides a largersurface area than a flat vertical surface having the same height. Moreheat can then be transferred through the recessed surface 48 thanthrough a flat vertical surface. Such a feature is desirable because ofthe confined height allowed for individual server unit subassemblies onthe support frame 26.

[0029] The fins 38 are all secured to a rear of the frame-level thermalinterface subcomponent 36. The fins 38 extend parallel to one anotherfrom the frame-level thermal interface subcomponent 36. The fins 38extend vertically parallel to one another along the frame-level thermalinterface subcomponent 36. Air can thus easily flow between the fins 38in a vertical direction.

[0030] The fins 40 are all secured to a front of the frame-level thermalinterface subcomponent 36 to the left of the recessed surface 48. Thefins 40 extend parallel to one another from a front of the frame-levelthermal interface subcomponent 36. The fins 40 extend parallel to oneanother horizontally along the frame-level thermal interfacesubcomponent 36. Air can thus flow in a horizontal direction between thefins 40.

[0031] The entire frame-level thermal interface component 28 is made ofcopper because of the high thermal conductivity of copper. Otherthermally conductive metals such as aluminum may provide adequatethermal conductivity in another embodiment. Heat can conduct through theportions 50 and 52 of the recessed surface 48 into the frame-levelthermal interface subcomponent 36. The frame-level thermal interfacesubcomponent 36 is made entirely of metal and is typically molded ormachined from a single piece of metal, so that the heat conductstherethrough to the fins 38. The heat can then convect from the fins 38to air flowing between the fins 38.

[0032] Referring again to FIG. 1, the frame-level thermal interfacecomponent 28 is mounted on the rear structural member 34. The recessedsurface 48 faces toward the front of the support frame 26, and the fins38 extend from a rear of the support frame 26.

[0033]FIG. 3 illustrates the components of the server unit subassembly24 in more detail. The server unit subassembly 24 includes a computerchassis 54, a circuit board 56, an electronic component in the form of acentral processing unit processor 58, and a evaporator unit loop 60. Thecircuit board 56 is secured on a base of the computer chassis 54. Theprocessor 58 is secured on the circuit board 56.

[0034] The evaporator unit loop 60 includes a evaporator unit 62, a hotvapor pipe 64, a cold liquid pipe 66, and a chassis-level thermalinterface component 68.

[0035] The evaporator unit 62 includes a heat-absorbing evaporator block70 and a capillary wicking material 72. The evaporator block 70 has aninternal volume 74, an inlet 76 into the internal volume 74, and anoutlet 78 out of the internal volume 74. The outlet 78 is at a higherelevation than the inlet 76.

[0036] A lower surface of the evaporator block 70 is located on theprocessor 58, and the evaporator block 70 is secured in such a position.The capillary wicking material 72 is located within the internal volume74. The capillary wicking material 72 is not as high as the internalvolume 74. A lower side of the capillary wicking material 72 is locatedon a lower internal surface of the internal volume 74. An upper side ofthe capillary wicking material 72 is located distant from an upperinternal surface of the internal volume 74. A gap is thus definedbetween the upper side of the capillary wicking material 72 and theupper internal surface of the internal volume 74. The inlet 76 leadsinto the internal volume 74 at a location below the upper side of thecapillary wicking material 72, and the outlet 78 leads out of the gapdefined in an upper portion of the internal volume 74.

[0037]FIGS. 4 and 5 illustrate the chassis-level thermal interfacecomponent 68 in more detail. The chassis-level thermal interfacecomponent 68 includes a chassis-level thermal interface subcomponent 80.The chassis-level thermal interface subcomponent 80 has a front surface82 and a tapered protruding rear surface 84. The rear surface 84 hasupper and lower portions 86 and 88 respectively. The portions 86 and 88are at an angle of approximately 30° relative to one another. The upperportion 86 is at an angle of approximately 5° relative to horizontal,and the lower portion 88 is at an angle of approximately 55° relative tohorizontal. The shape of the rear surface 84 thus matches, and iscomplementary to, the shape of the recessed surface 48 in FIG. 3.

[0038]FIG. 6 illustrates the chassis-level thermal interface component68 in exploded form. A wall 90 of the chassis-level thermal interfacesubcomponent 80 is removed. An internal volume 92 is defined inside thechassis-level thermal interface subcomponent 80. An upper portion of thewall 90 forms the upper portion 86 of the rear surface 84. A lowersurface of the wall 90 defines one side of the internal volume 92.

[0039] An inlet 94 is formed into the internal volume 92, and an outlet96 is formed out of the internal volume 92. A fluid can flow through theinlet 94 into the internal volume 92, and flow from the internal volume92 out of the outlet 96. The fluid flows over the wall 90 while in theinternal volume 92. Three baffles 98 are located in the internal volume92. The baffles 98 divide the internal volume 92 into four chambers 100.The fluid flowing through the internal volume 92 flows sequentiallythrough the chambers 100. The fluid is located against a respectiveportion of the wall 90 while located in each one of the chambers 100.The baffles 98 extend a fluid flow path through the internal volume,with a corresponding increase in effective heat-exchanging length,thereby increasing the rate of heat transfer.

[0040] Reference is again made to FIG. 3. Opposing ends of the hot vaporpipe 64 are connected respectively to the outlet 78 out of theevaporator block 70 and the inlet 94 into the chassis-level thermalinterface subcomponent 80. Opposing ends of the cold liquid pipe 66 areconnected respectively to the outlet 96 out of the chassis-level thermalinterface subcomponent 80 and the inlet 76 into the evaporator block 70.The evaporator block 70 is located toward the front, and thechassis-level thermal interface component 68 is located toward the rearof the server unit subassembly 24. The rear surface 84 faces toward therear of the server unit subassembly 24. A bracket 101 mounts rear endsof the pipes 64 and 66 in a relatively stationary position. The bracket101 substantially disallows movement of the chassis-level thermalinterface component 68 in a horizontal direction, while still allowingfor a small amount of vertical movement of the chassis-level thermalinterface component 68, relative to the computer chassis 54.

[0041] Reference is again made to FIG. 1. A rear of the computer chassis54 is partially inserted into the front of the support frame 26. A rightedge of the computer chassis 54 rests on the side rail 32A, and a leftedge of the computer chassis 54 rests on the side rail 32B. Thechassis-level thermal interface component 68 is located distant from theframe-level thermal interface component 28.

[0042] An operator slides the computer chassis 54 toward the rear of thesupport frame 26. Such movement of the computer chassis 54 moves thechassis-level thermal interface component 68 into engagement with theframe-level thermal interface component 28. The upper and lower portions86 and 88 of the rear surface 84 shown in FIGS. 4 and 5 respectivelymake contact with the upper and lower surfaces 52 and 50 of the recessedsurface 48 shown in FIG. 2.

[0043] The angular profile of the rear surface 84 compensates for slightmisalignment between the rear surface 84 and the recessed surface 48.The upper portion 86 may, for example, make contact with the upperportion 52 before the lower portion 88 makes contact with the lowerportion 50. The chassis-level thermal interface component 68 is guideddown along the upper portion 52 until the lower portions 84 and 50contact one another, and the bracket 101 allows for such movement. FIG.7 illustrates the server computer system 20 after full engagement of thechassis-level thermal interface component 68 with the frame-levelthermal interface component 28.

[0044] In use, heat is generated by the processor 58 when operated. Theprocessor 58 may, for example, generate at least 100 W of heat.Approximately 1 percent of the heat transfers to the circuit board 56.The other 99 percent of the heat conducts from the processor 58 througha lower wall of the evaporator block 70 into a liquid in the capillarywicking material 72. The heat evaporates the liquid, and a resultingvapor collects in the gap above the capillary wicking material 72. Thevapor leaves the gap through the outlet 78 into the hot vapor pipe 64.More liquid flows through the inlet 76 into the capillary wickingmaterial 72, replacing the vaporized fluid. A pump effect is therebycreated, which circulates the fluid through the evaporator unit loop 60.The evaporator unit 62 thus has the advantage that it moves the fluid ina pump-like manner without the need for a pump having moving parts.

[0045] The vapor flows through the hot vapor pipe 64 to thechassis-level thermal interface component 68. Referring to FIG. 6, thevapor flows through the inlet 94 and then sequentially through thechambers 100 over the wall 90. The heat conducts from the vapor throughthe wall 90 to the portion 86. The vapor condenses while heat is beingtransferred therefrom, so that by the time that the vapor leaves thechambers 100 through the outlet 96, the vapor is transformed into aliquid. Heat is transferred in a similar manner from the vapor to theportion 88. Referring again to FIG. 3, the liquid returns through thecold liquid pipe 66 to the inlet 76 of the evaporator block 70.

[0046] Referring to FIG. 2, the heat conducts to the upper and lowerportions 52 and 50 to the frame-level thermal interface subcomponent 36.The heat then conducts to the first set of fins 38. Substantially all ofthe heat generated by the processor 58 reaches the fins 38. Less than 2percent of the heat transfers through the circuit board 56 and is lostthrough other mechanisms.

[0047] As shown in FIG. 7, the server computer system 20 furtherincludes a fan assembly 102. The fan assembly 102 includes a fan housing104 and a fan 106. The fan housing 104 is secured to the computerchassis 54. The fan 106 is secured to the fan housing 104, and is drivenby an electric motor (not shown), so that the fan 106 may rotate. Arotation axis of the fan 106 extends from the left to the right of thecomputer chassis 54, so that the fan 106 directs air from the left tothe right. The fan assembly 102 is moved into a position to the left ofthe fins 38 when the computer chassis 54 is inserted into the supportframe 26. The fan 106 recirculates air within the chassis 54 and directsthe air from the left to the right over the fins 38. The heat convectsfrom the air flowing over the fins 38 to the fins 38. The heat thenconducts from the fins 38 to the fins 40. The fins 40 thus receive heatfrom the air in the chassis 54 and from the processor 58.

[0048]FIG. 8 illustrates further components of the server computersystem 20. The server computer system 20 includes a plurality of siderails 32A, a plurality of side rails 32B, a plurality of rear structuralmembers 34, a plurality of frame-level thermal interface components 28,and an air duct 110. The side rails 32A are all located above oneanother. Similarly, the side rails 32B are all located above oneanother, and the rear structural members 34 are all located above oneanother. A plurality of server unit subassemblies 24 are insertable intothe support frame 26. The server unit subassemblies 24 are separatelyinsertable above one another, with respective right edges of thecomputer chassis thereof on respective ones of the right side rails 32A,and respective left edges of the computer chassis on respective ones ofthe left side rails 32B. The server unit subassemblies 24 may beidentical to one another, and each may include a respectivechassis-level thermal interface component 68.

[0049] Each frame-level thermal interface component 28 is secured to arespective one of the rear structural members 34. The frame-levelthermal interface components 28 are located above one another. The fins38 of all the frame-level thermal interface components 28 are verticallyaligned with one another. Each server unit subassembly 24 has arespective chassis-level thermal interface component 68 that mates witha respective one of the frame-level thermal interface components 28.Heat thus transfers from a processor of each respective server unitsubassembly 24 to the fins 38 of a respective frame-level thermalinterface component 28.

[0050] The air duct 110 has an internal cavity 112, an air inlet 114into the bottom of the internal cavity 112, and an air outlet 116 out ofa top of the internal cavity 112. A thermal interface opening 118 isalso formed in a front of the air duct 110.

[0051] Reference is now made to FIGS. 8 and 9 in combination. Thethermal interface opening 118 is located over the fins of theframe-level thermal interface component 28. The thermal interfaceopening 118 has a rectangular opening which mates with a rectangularprofile of the frame-level thermal interface components 28 located aboveone another.

[0052] The air outlet 116 is connected to a room-cooling duct (notshown). A negative pressure is created at the air outlet 116. Air atambient temperature and pressure is drawn into the air inlet 114 andflows through the internal cavity 112 to the air outlet 116.Substantially all the air that is drawn in through the air inlet 114leaves through the air outlet 116. A fan may be mounted in the airoutlet 116 to draw air through the air duct 110.

[0053] The air flows vertically upward over the fins 38 while flowingthrough the internal cavity 112. The air flows sequentially over thefins 38 of one of the frame-level thermal interface components 28, andthen over the fins 38 of another one of the frame-level thermalinterface components 28 located above the previous frame-level thermalinterface component 28. Because the fins 38 are all vertically alignedand the direction of flow of air is vertical, the air flows between thefins 38. Heat convects from the fins 38 to the air flowing over the fins38, whereafter the air leaves via the air outlet 116 into an air duct ofthe room. It can thus be seen that an efficient manner is provided tocool the processors of all the server unit assemblies 24 by transferringheat to a common stream of air. The flow of the air is controlled sothat the air does not again enter the room, which may require additionalair conditioning.

[0054] Should any maintenance be required on any server unit subassembly24, the server unit subassembly 24 is simply pulled out of the front ofthe support frame 26. The mating surfaces of the chassis-level thermalinterface component 68 and the frame-level thermal interface component28 simply separate. There are no screws or structures that provide apermanent connection between the thermal components of the server unitsubassembly 24 and the thermal components of the server computer framesubassembly 22. There are thus no such fasteners or structures that haveto be undone in order to remove the server unit subassembly 24 from thesupport frame 22 (with the exception of a ratchet mechanism, which isdescribed below).

[0055]FIGS. 10 and 11 illustrate further components of the servercomputer system 20 that are used for taking up tolerances in the supportframe 26. The server computer system 20 further includes a chassis-levelconnector 130, a support board 132, springs 134, a frame-level connector136, and cables 138.

[0056] The chassis-level connector 130 is secured to the computerchassis 54. The chassis-level connector 130 is electrically connected tothe circuit board 56 shown in FIG. 3. Electric signals can betransmitted between the chassis-level connector 130 and the processor 58through the circuit board 56.

[0057] Each spring 134 has one end which is secured against the supportframe 26, and an opposing end which is secured against the support board132. The support board 132 is movably secured to the support frame 26with the springs 134 between them. Movement of the support board 132toward the support frame 26 compresses the springs 134. The springs 134thereby create a force which tends to move the support board 132 awayfrom the support frame 26. The magnitude of the force increases linearlywith movement of the support board 132 toward the rear of the supportframe 26.

[0058] The cables 138 are connected to the frame-level connector 136.The frame-level connector 136 is secured to the support board 132. Theframe-level connector 136 moves together with the support board 132relative to the support frame 26. Flexibility of the cables 138 allowfor movement of the frame-level connector 136 relative to the supportframe 26.

[0059] The chassis-level connector 130 engages and mates with theframe-level connector 136 when the computer chassis 54 is moved into thesupport frame 26. An insertion force between the frame-level connector136 and the chassis-level connector 130 tends to move the chassis-levelconnector 130 into disengagement from the frame-level connector 136. Thechassis-level connector 130 thus tends to move in a direction oppositeto the direction in which the computer chassis 54 is inserted into thesupport frame 26.

[0060] Further movement of the computer chassis 54 into the supportframe 26 also moves the support board 132 toward the support frame 26.Such movement or “float” of the support board 132 allows the computerchassis 54 to be inserted to a required depth into the support frame 26.Tolerances in assembly and manufacture of the support frame 26 arecompensated for in this manner. The support board 132 also includessubcomponents that compensate for tolerances in the support frame 26 inthree dimensions. Movement of the support board 132 compresses thesprings 134, which creates a force which tends to move the support board132 in a direction opposite to the direction in which the computerchassis 54 is inserted into the support frame 26. The springs 134 thustend to move the computer chassis 54 out of the front of the supportframe 26. The force created by the springs 134 is much larger than theinsertion force between the frame-level connector 136 and thechassis-level connector 130, so that the force of the springs 134 onlycomes into play after the chassis-level connector 130 is fully matedwith the frame-level connector 136. Compression of the springs iscontinued until the chassis-level interface component 68 mates with theframe-level thermal interface component 28.

[0061]FIG. 12 illustrates apparatus 140 of the server computer system20, which is used for controlling the depth to which the computerchassis 54 is inserted into the support frame 26. The apparatus 140includes a ratchet mechanism 142 and a disengaging lever 144.

[0062] The ratchet mechanism 142 includes a ratchet gear 146 and aratchet pawl 148. The ratchet gear 146 is secured to the computerchassis 54. The ratchet gear 146 has a plurality of ratchet teeth 150.Each ratchet tooth 150 has a left surface which is substantiallyvertical, and a right surface which is at an angle relative to vertical.

[0063] The ratchet pawl 148 is pivotally secured to the side rail 32A.Clockwise movement of the ratchet pawl 148 moves the ratchet pawl 148into a gap between two of the teeth 150. Counterclockwise movement ofthe ratchet pawl 148 moves the ratchet pawl 148 out of the gap. Theratchet pawl 148 is biased in a clockwise direction, or moves in aclockwise direction under gravity. The disengaging lever 144 is securedto the ratchet pawl 148 so as to move together with the ratchet pawl 148either in a clockwise direction or in a counterclockwise direction. Thedisengaging lever 144 has a surface 152 which can be manually depressed.Depressing of the surface 152 rotates the disengaging lever 152 and theratchet pawl 148 in a counterclockwise direction.

[0064] The computer chassis 54 moves from the left to the right alongthe side rail 32A when the computer chassis 54 is inserted into thesupport frame 26. The ratchet gear 146 moves together with the computerchassis 54 relative to the side rail 32A. The ratchet pawl 148 moves ina ratchet-like manner into successive gaps between subsequent ones ofthe teeth 150 when the computer chassis 54 is moved from left to right.Movement of the computer chassis 54 from right to left is, however,disallowed because the ratchet pawl 148 has a surface on the right whichcatches on a left surface of a respective selected tooth 150A. Theratchet pawl 148 and the selected tooth 150A thus prevent the computerchassis 54 from moving out of the support frame 26 under the force ofthe springs 134 and the insertion force between the chassis-levelconnector 130 and the frame-level connector 136.

[0065] The surface 152 is depressed should it be required to remove thecomputer chassis 54 out of the support frame 26. Depression of thesurface 152 rotates the ratchet pawl 148 out of the gap between theselected tooth 150A and the tooth to the left thereof, so that theratchet pawl 148 disengages from the selected tooth 150A. The springs134 then bias the support board 132 and the computer chassis 54 in anopposite direction out of the support frame 26. The computer chassis 54moves out of the support frame 26 under the forces of the springs 134.Such movement of the computer chassis 54 out of the support frame 26disengages the chassis-level thermal interface component 68 from theframe-level thermal interface component 28. The momentum of the serverunit subassembly 24 also disengages the chassis-level connector 130 fromthe frame-level connector 136.

[0066]FIG. 13 illustrates all the other server unit subassemblies 24 ofthe server computer system 20. The server unit subassemblies 24 areidentical, and are inserted in rack form into the support frame 26. Aplurality of support boards 32 is secured to the support frame, eachnext to a respective set of springs 134.

[0067] In the descriptions of the embodiments that follow, for purposesof efficacy, not all details thereof are described and discussed indetail. Instead, the description of each of the embodiments that followprimarily indicates differences between the specific embodimentdescribed and an embodiment or embodiments that have been describedpreviously. Unless specifically stated otherwise or unless it can beinferred, therefore, it can be assumed that the details of subsequentembodiments are the same as details of embodiments that have beendescribed previously.

[0068]FIGS. 14 and 15 illustrate a frame-level thermal interfacecomponent 228 according to another embodiment of the invention. Theframe-level thermal interface component 228 includes a frame-levelthermal interface subcomponent 236 and a set of fins 240. Theframe-level thermal interface subcomponent 236 has a recessed frontsurface 248 having the same profile as the recessed surface 48 of theframe-level thermal interface component 28 of FIG. 2.

[0069] The frame-level thermal interface subcomponent 236 has aninternal volume 250, an inlet 252 into the internal volume 250, and anoutlet 254 out of the internal volume 250. The frame-level thermalinterface subcomponent 236 further has a baffle 256 in the internalvolume 250. The baffle 256 divides the internal volume 250 into firstand second chambers 258 and 260. A liquid circulation vent 262 connectsthe chamber 258 to the chamber 260. The inlet and the outlet 252 and 254are located on the same side of the frame-level thermal interfacesubcomponent 236. The recessed surface 248 is an outer surface of awall, and the wall also has an inner surface defining the internalvolume 250. A liquid can enter through the inlet 252 and then flowsequentially through the chambers 258 and 260 before exiting through theoutlet 254. Liquid flows over the wall while in the chamber 258 and inthe chamber 260. Heat conducts from the surface 248 through the wall andthen convects to the liquid while the liquid is in the chamber 258 andwhile the liquid is in the chamber 260. The baffle 256 extends a fluidflow path through the internal volume 250, with a corresponding increasein contact between the liquid and the surface 248, thereby increasingthe rate with which heat convects to the fluid.

[0070]FIG. 16 illustrates a server computer frame subassembly 270 of aserver computer system according to another embodiment of the invention.The server computer frame subassembly 270 includes a plurality offrame-level thermal interface components 228 such as the frame-levelthermal interface component of FIG. 14. When comparing FIG. 16 with FIG.8, it will be seen that the frame-level thermal interface components 228of FIG. 16 are instead of the frame-level thermal interface components28 of FIG. 8. The server computer frame subassembly 270 further includesan inlet pipe 272 and outlet pipe 274. The inlets (252 in FIG. 15) ofthe respective frame-level thermal interface components 228 “T” out ofthe inlet pipe 272. The outlets (254 in FIG. 15) “T” into the outletpipe 274.

[0071] In use, liquid coolant is introduced into a lower end of theinlet pipe 272. The liquid coolant flows from the inlet pipe 272 intothe respective inlets of the respective frame-level thermal interfacecomponents 228. The liquid coolant flows in parallel through therespective frame-level thermal interface components 228, where it isheated. The liquid coolant then flows out of the outlets of theframe-level thermal interface components 228 to the outlet pipe 274. Theliquid coolant may then be at a temperature of, for example, 25° C. Theliquid coolant may be pre-processed to a temperature lower than ambient,e.g., 15° C., to increase the amount of heat that can be transferred ina given period of time.

[0072] The liquid coolant may also cool the fins 240 in FIG. 14. Heatcan transfer from the internal volumes of computer chassis to the fins240, and then from the fins 240 to the liquid coolant. If the coolantused is a liquid coolant, larger amounts of energy may be transferredthereto when compared to air, owing to, in most cases, the greater heatcapacity of the liquid coolant.

[0073] While certain exemplary embodiments have been described and shownin the accompanying drawings, it is to be understood that suchembodiments are merely illustrative and not restrictive of the currentinvention, and that this invention is not restricted to the specificconstructions and arrangements shown and described since modificationsmay occur to those ordinarily skilled in the art.

What is claimed:
 1. A chassis-level thermal interface component,comprising: a chassis-level thermal interface component subcomponent forsecuring to a chassis having a processor secured thereto, having a wallwith an outer surface for mating with an outer surface of a framecomponent, the outer surface having at least first and second portionsthat are at an angle other than 0° relative to one another, and aninternal volume at least partially defined by an inner surface of thewall, an inlet into the internal volume, and an outlet out of theinternal volume.
 2. The chassis-level thermal interface component ofclaim 1 wherein the first and second portions are straight.
 3. Thechassis-level thermal interface component of claim 1 wherein the inletis through a surface of the chassis-level thermal interface componentsubcomponent other than the outer surface of the chassis-level thermalinterface component subcomponent.
 4. The chassis-level thermal interfacecomponent of claim 1 wherein the chassis-level thermal interfacecomponent subcomponent has a baffle separating the internal volume intoat least first and second chambers.
 5. The chassis-level thermalinterface component of claim 4 wherein a fluid flows sequentiallythrough the inlet, the first chamber, the second chamber, and theoutlet.
 6. The chassis-level thermal interface component of claim 5wherein the fluid flows over the internal surface when located in boththe first and second chambers.
 7. The chassis-level thermal interfacecomponent of claim 6 wherein the first and second chambers are bothdefined by a first portion of the internal surface, the first portion ofthe internal surface and the first portion of the outer surface directlyopposing one another on opposite sides of the wall.
 8. A chassis-levelthermal interface component, comprising: a chassis-level thermalinterface component subcomponent for securing to a chassis having aprocessor secured thereto, having a wall with an outer surface formating with an outer surface of a frame component, the outer surfacehaving at least first and second portions that are at an angle otherthan 0° relative to one another, and an internal volume at leastpartially defined by an inner surface of the wall, an inlet through asurface other than the outer surface into the internal volume, and anoutlet through a surface other than the outer surface out of theinternal volume; a baffle separating the internal volume into at leastfirst and second chambers, a fluid flowing sequentially through theinlet, the first chamber, the second chamber, and the outlet.
 9. Thechassis-level thermal interface component of claim 8 wherein the fluidflows over the internal surface when located in both the first andsecond chambers.
 10. The chassis-level thermal interface component ofclaim 9 wherein the first and second chambers are both defined by afirst portion of the internal surface, the first portion of the internalsurface and the first portion of the outer surface directly opposing oneanother on opposite sides of the wall.
 11. A server unit subassembly,comprising: a chassis insertable into a frame; an electronic componenton the chassis; a chassis-level thermal interface component thermallycoupled to the electronic component so that heat generated by theelectronic component transfers to the chassis-level thermal interfacecomponent, the chassis-level thermal interface component having an outersurface that mates with an outer surface of a frame component on theframe when the chassis is inserted into the frame, so that the heat cantransfer from the chassis-level thermal interface component through theouter surfaces to the frame component.
 12. The server unit subassemblyof claim 11 wherein the outer surface of the chassis-level thermalinterface component has first and second portions that are at an angleother than 0° relative to one another.
 13. The server unit subassemblyof claim 12 wherein the first and second portions are straight.
 14. Theserver unit subassembly of claim 11 wherein the chassis-level thermalinterface component includes a chassis-level thermal interface componentsubcomponent with a wall, the outer surface being an outer surface ofthe wall, an internal volume at least partially defined by the wall, aninlet into the internal volume, and an outlet out of the internalvolume.
 15. The server unit subassembly of claim 14 wherein the inlet isthrough a surface of the chassis-level thermal interface component otherthan the outer surface thereof that mates with the outer surface of theframe component.
 16. The server unit subassembly of claim 14 wherein thechassis-level thermal interface component subcomponent has a baffleseparating the internal volume into at least first and second chambers.17. The server unit subassembly of claim 16 wherein a fluid flowssequentially through the inlet, the first chamber, the second chamber,and the outlet.
 18. The server unit subassembly of claim 17 wherein thefluid flows over the internal surface wherein located in both the firstand second chambers.
 19. The server unit subassembly of claim 18 whereinthe first and second chambers are both defined by a first portion of theinternal surface, the first portion of the internal surface and thefirst portion of the outer surface directly opposing one another onopposite sides of the wall.